The present invention relates to mobile Internet access and is applicable in particular, though not necessarily, to mobile Internet access achieved directly from the radio network of a mobile telecommunications network.
Subscribers to existing mobile telecommunications networks may under certain circumstances access the Internet using either an Internet enabled mobile telephone (a device often referred to as a xe2x80x9ccommunicatorxe2x80x9d) or by coupling a palmtop or laptop computer to a conventional mobile telephone, for example using a software or hardware modem.
In digital mobile telephone networks, such as the European GSM (Global System for Mobile communications) system, a mobile telecommunications network can be divided into two parts. The first part is referred to as the xe2x80x9cradio networkxe2x80x9d and consists of base stations (BSs) and base station controllers (BSCs) where a single BSC controls a number of BSs. The second part of the network is referred to as the xe2x80x9ccore networkxe2x80x9d and comprises mobile switching centres (MSCs), each MSC being responsible for a number of BSCs. An MSC is analogous to an exchange of a conventional telephone network. Internet traffic is carried over a circuit switched connection established between the mobile terminal and an Internet Service Provider (ISP) via the core network.
The development of future mobile communication standards is currently ongoing. In particular, an enhancement to GSM known as General Packet Radio Service (GPRS) is being developed to introduce a packet switched service into GSM. The introduction of GPRS will effectively add an additional core network to GSM systems, with switching functions being performed in the GPRS core network by Serving GPRS Support Nodes (SGSNs) and Gateway GPRS Support Nodes (GGSNs). A third generation digital system is also under development and is known as Universal Mobile Telecommunications System (UMTS). UMTS is likely to incorporate GPRS or a similar packet switched system.
Under current proposals, in both GSM GPRS and UNMTS systems, Internet access will be obtained via the packet switched core network. When a mobile terminal requests Internet access, the request is directed via a BS and a Radio Network Controller (RNC, equivalent to the traditional BSC) to a GGSN. The GGSN in turn directs the request to an Internet Access Server (IAS). The IAS is typically operated by an Internet Service Provider (ISP) which is independent from the operator of the mobile network. However, the IAS may alternatively be operated by the mobile network operator. In either case, the IAS allocates to the calling mobile terminal an Internet Protocol (IP) address. According to the existing Internet Protocol version 4 (IPv4), the IP address has 32 bits. According to the proposed Internet Protocol version 6 (IPv6), the IP address is enlarged to 128 bits and comprises a 64 bit routing prefix which uniquely identifies the IAS to the Internet, and also a 64 bit host prefix which uniquely identifies the mobile terminal to the IAS.
The allocated IP address is returned to the mobile terminal via the packet switched core network and the radio network whereupon the mobile terminal is able to commence an Internet session. Assuming that the mobile terminal is registered with its home network when the Internet access is requested, the Internet session is routed via the GGSN of the home network. However, when a mobile terminal is xe2x80x9croamingxe2x80x9d and is registered with a foreign network, the Internet session may be conducted via both an SGSN of the visited network and possibly a GGSN of the home or foreign network.
As subscribers of existing digital networks may be aware, Internet access via a mobile terminal is generally extremely slow and unreliable. This is due in part to the need for a slow set-up phase, required each time a new transfer session is commenced, during which session parameters including an IP address are negotiated. Another reason for slow speed (as well as unreliability) is the possibly large distance between the node (e.g. IAS) which allocates an IP address and the mobile terminal, possibly involving one or more intermediate nodes. IP datagrams must be tunnelled between the two end points, often involving additional protocols (e.g. Point-to Point Protocol, Layer 2 Tunnelling Protocol, etc), consuming extra processing and transmission capacity.
Whilst the current proposals for GPRS and UMTS will result in a faster and more reliable radio connection between a mobile terminal and the radio and core networks, they will not eliminate the need to negotiate the IP address prior to commencing an Internet session nor the need to route IP datagrams via one or more switching nodes of the packet switched core network(s).
It is an object of the present invention to overcome or at least mitigate the above noted disadvantages of existing and currently proposed mobile telecommunications networks. In particular, it is an object of the present invention to eliminate or at least obviate the need to negotiate an IP address between a mobile terminal and an node of the mobile network prior to commencing an Internet session.
According to a first aspect of the present invention there is provided a method of allocating an Internet protocol (IP) address to a mobile wireless terminal within a mobile telecommunications network, the method comprising repeatedly broadcasting at least a routing prefix over a radio channel of the network, wherein the routing prefix may be received by a mobile terminal listening to said broadcast and thereafter incorporated into an IP address.
Embodiments of the present invention enable a mobile terminal to be provided with a routing prefix prior to the mobile terminal commencing an Internet session. The mobile terminal may therefore in turn generate an IP address prior to such commencement.
The routing prefix transmitted by the mobile network may be unique to the radio network. Alternatively, the broadcast routing prefix may be unique to a node of the radio network, such as a Base Station Controller (BSC) of a GSM network or a Radio Network Controller (RNC) of a UMTS network. These possibilities allow the radio network/Radio Network Controller to be connected directly to the Internet and avoid the need to route a subsequent Internet session via an MSC/GGSN or analogous node of a core network.
Preferably, the mobile telecommunications network uses the GPRS or UMTS protocols over the air interface coupling mobile terminals to the network. Alternatively, a conventional digital protocol such as GSM or PDC may be used. The invention is also applicable to local mobile networks such as the proposed Broadband Radio Networks (BRANs) and networks utilising Bluetooth.
Preferably, said routing prefix is broadcast over a broadcast channel of the mobile network. Alternatively however, the routing prefix may be broadcast using a so-called multi-cast radio channel.
According to a second aspect of the present invention there is provided apparatus for allocating an Internet Protocol (IP) address to a mobile wireless terminal within a telecommunications network, the apparatus comprising means for continuously broadcasting at least a routing prefix of an IP address over the air interface of the telecommunications network, and means associated with the mobile terminal for listening to said broadcasts to obtain the routing prefix and for generating an IP address using the routing prefix.
According to a third aspect of the present invention there is provided an Internet enabled mobile wireless terminal, the mobile terminal being arranged in use to listen to a radio channel of a mobile telecommunications network and to obtain from the radio channel a broadcast routing prefix which can be used by the mobile terminal to generate an IP address.